Automotive Onboard Fire Suppression System Reservoir Having Multifunction Control Valve

ABSTRACT

An automotive vehicle includes a vehicle body and at lease one reservoir containing a fire suppressant agent. A distribution system receives the fire suppression agent from the reservoir and conducts the agent to at least one location about the vehicle&#39;s body in response to the determination by a sensor system and controller that the vehicle has been subjected to a significant impact. The reservoir includes a multifunction valve element which controls pressure and vacuum within the reservoir during standby operation, while causing the fire suppressant agent to be directed through the distribution system if the propellant activates.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/907,134, filed Mar. 22, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automotive vehicle having an onboardapparatus for suppressing a vehicle fire.

2. Disclosure Information

Police vehicles are subject to increased exposure to collisions,particularly high-speed rear-end collisions, arising from the need forpolice officers to stop on the shoulders, or even in the traffic lanes,of busy highways. Unfortunately, other motorists are known to collidewith police vehicles employed in this manner. These accidents cancompromise the fuel system on any vehicle and may cause fires. Thepresent system is designed to suppress the spread of, or potentially, toextinguish such a fire. U.S. Pat. No. 5,590,718 discloses an anti-firesystem for vehicles in which a number of fixed nozzles are furnishedwith a fire extinguishing agent in response to an impact sensor. Thesystem of the'718 patent suffers from a problem in that the fixednozzles are not suited to the delivery of the extinguishing agent atground level. Also, the '718 patent uses a valving system which couldbecome clogged and therefore inoperable. U.S. Pat. No. 5,762,145discloses a fuel tank fire protection device including a powderedextinguishing agent panel attached to the fuel tank. In general, powderdelivery systems are designed to prevent ignition of fires and aredeployed upon impact. As a result, the powder may not be able to followthe post-impact movement of the struck vehicle and may not be able toprevent the delayed ignition or re-ignition of a fire.

The present fire suppression system provides significant advantages, ascompared with prior art vehicular fire suppression systems.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an onboard firesuppression system includes at least one reservoir containing a firesuppressant agent, and a propellant, operatively associated with thereservoir, for expelling the fire suppressant agent from the reservoirunder pressure. A distribution system receives fire suppression agentexpelled from the reservoir and distributes it to at least one location.A multi-function control valve, operatively connected with thereservoir, maintains pressure within the reservoir within apredetermined range during standby operation, with the control valveclosing in the event that the propellant is activated. Themulti-function control valve includes a vacuum responsive element, astandby pressure relief element, and a high flow closure element. Thiscontrol valve extends through a wall of the reservoir.

The valving functions of a multifunction control valve according to anaspect of the present invention are performed by a vacuum responsiveelement having an inward-opening poppet, by a standby pressure reliefelement having an outward-opening poppet, and by an outward-closingpoppet which is responsive to high rate flow of the suppressant agent.The outward closing poppet closes in response to elevated suppressantflow rate and elevated suppressant pressure which normally accompaniesdischarge of the suppressant from the reservoir. The inward-openingpoppet opens in the event that the pressure within the reservoir fallsbelow a predetermined minimum pressure. The outward-opening poppet movesto an open position in the event that pressure within the reservoirexceeds a predetermined maximum static pressure, with the highflow-responsive poppet closing in the event that the pressure producedby the propellant exceeds a predetermined maximum dynamic pressureproduced by an activated propellant.

According to another aspect of the present invention, the inward-openingpoppet and the outward-opening poppet are resiliently biased intonormally-closed positions, with the outward-closing poppet beingresiliently biased into a normally-open position.

According to another aspect of the present invention, a propellant mayeither be housed within the reservoir or external to the reservoir.

According to another aspect of the present invention, the multi-functioncontrol valve may be contained within a filler port plug for thereservoir.

It is an advantage of a onboard fire suppression system according to thepresent invention that pressure changes due to environmental conditionssuch as changes in altitude and changes in ambient temperature may beaccommodated by a fire suppression system reservoir without concomitantmaterial fatigue due to flexing which could otherwise be caused by suchchanges in pressure.

Other advantages, as well as features of the present invention willbecome apparent to the reader of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ghost perspective view of an automotive vehicle having afire suppression system according to the present invention.

FIG. 2 is an exploded perspective view of a portion of a firesuppression system according to the present invention.

FIG. 3 is a perspective view of a control module used with a systemaccording to the present invention.

FIG. 4 is a perspective view of a manually activatable switch used witha fire suppression system according to the present invention.

FIG. 5 illustrates a portion of a wiring harness used with the presentsystem.

FIG. 6 is a flowchart showing a portion of the logic used to control asystem according to the present invention.

FIG. 7 is a cutaway perspective view of a fire suppression agentreservoir according to one aspect of the present invention.

FIG. 8 is a perspective view of a variable geometry fire suppressionagent nozzle according to one aspect of the present invention.

FIG. 9 is a block diagram of a fire suppression system and withadditional components for occupant restraint according to one aspect ofthe present invention.

FIG. 10 is a perspective view of a vehicle having a fire suppressionsystem with a reservoir having a multifunction control valve accordingto one aspect of the present invention.

FIG. 11 is a perspective view of a suppression agent reservoir accordingto one aspect of the present invention.

FIG. 12 is a sectional view of the reservoir of FIG. 11, taken along theline 12-12 of FIG. 11.

FIG. 13 is an enlarged view of the control valve shown in FIG. 12.

FIG. 14 is perspective view similar to FIG. 11, but illustrating areservoir teamed with an external propellant.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, vehicle 10 has a passenger airbag restraint 48 and adriver's airbag restraint 50 mounted adjacent steering wheel 52. A firesuppression system includes controller 66 which is mounted upon floorpan 68 of vehicle 10, and reservoirs 18 which are mounted under floorpan 68 in the so-called kick-up area adjoining the rear axle of vehicle10. Those skilled in the art will appreciate in view of this disclosurethat additional passenger restraint devices, such as seat beltpretensioners and side airbags, may be installed in a vehicle andcontrolled at least in part by, or in conjunction with, controller 66.

FIG. 1 shows not only reservoirs 18 but also a portion of right and leftside fire suppression conduits 28, as well as fixed geometry nozzles 30and variable geometry nozzles 36. As seen in FIG. 1, variable geometrynozzles 36 project downwardly to allow fire suppression agent to beexpelled from reservoirs 18 and placed at a low angle to the groundsurface the vehicle is operating upon. This mode of operation ispossible because variable geometry nozzles 36 are, as shown in FIG. 2,telescopingly extensible. This telescoping feature, which is shown ingreater detail in FIG. 8, is produced by a sliding spray head, 40, whichis slidingly engaged with conduit 28 such that gas pressure withinconduit 28 forces spray head 40 downwardly into its extended position,causing fire suppression agent 22 to be discharged through a number ofholes 42 formed in spray head 40. As shown in FIG. 2, at least twovariable geometry nozzles 36 may be employed with single reservoir 18,along with at least two fixed nozzles 30 which are spray bars eachhaving a number of orifices 34. While in their normally closed state,variable geometry nozzles 36 are liquid-tight by virtue of seals 46,which are interposed between an end of each of spray heads 40 and thecorresponding ends of conduits 28. In a preferred embodiment, seals 46comprise elastomeric boots attached to an outer surface of conduit 28.Seals 46 are simply sheared by the deploying spray head 40 when thepresent system is discharged. Fixed nozzles 30 are also renderedliquid-tight by covers 44, which are simply blown off when the presentsystem is discharged. The sealing of nozzles 30 and 36 is important,because this prevents the ingress of road splash, which could block thesystem in sub-freezing weather or cause corrosion or blockage due to mudor other foreign matter.

Additional details of reservoir 18 are shown in FIG. 7. Tank 90 containsapproximately 1.5 L of fire suppression agent 22, and a propellant 92.Propellant 92 includes two squibs (not shown) which are activatedsimultaneously by controller 66 via lines 91 so as to release a largeamount of gas, forcing fire suppressant agent 22 from tank 90 and intodistribution system 26, including conduit 28 and the various fixed andvariable geometry nozzles. A preferred propellant, marketed by PrimexAerospace Company as model FS01-40, is a mixture includingaminotetrazole, strontium nitrate, and magnesium carbonate. This isdescribed in U.S. Pat. No. 6,702,033, which is hereby incorporated byreference into this specification.

Those skilled in the art will appreciate in view of this disclosure thatother types of propellants could be used in the present system, such ascompressed gas canisters and other types of pyrotechnic and chemicaldevices capable of creating a gas pressure force in a vanishingly smallamount of time. Moreover, fire suppressant agent 22, which preferablyincludes a water-based solution with hydrocarbon surfactants,fluorosurfactants, and organic and inorganic salts sold under the tradename LVS Wet Chemical Agent® by Ansul Incorporated, could comprise othertypes of agents such as powders or other liquids, or yet other agentsknown to those skilled in the art and suggested by this disclosure. Iftwo reservoirs 18 are employed with a vehicle, as is shown in FIG. 1,all four squibs will be deployed simultaneously.

FIG. 4 shows manually activatable switch 54 for use with the presentsystem. As shown in FIG. 1, switch 54 may be advantageously located onthe headliner of vehicle 10 between the sun visors, or at any otherconvenient position. To use this switch 54, hinged clear cover 56 isfirst opened by pressing on cover 56. Thereafter, the fire suppressionsystem may be triggered by manually pressing pushbutton 58. If thevehicle occupants are not disposed to release cover 56, the system maybe triggered by merely sharply depressing cover 56, thereby closingcontacts (not shown) contained within platform 60.

Because the present system is intended for use when the vehicle hasreceived a severe impact, controller 66, which is shown in FIG. 3,contains a redundant power reserve or supply, which allows operation ofthe fire suppression system for about nine seconds, even if controller66 becomes isolated from the vehicle's electrical power supply. Wiringharness 80, as shown in FIG. 5, is armored, and has a para-aramid fiberinner sheath, 82, of about 2 mm in thickness, which helps to shield theconductors within harness 80 from abrasion and cutting during a vehicleimpact event. This para-ramid fiber is sold under the trade name KEVLAR®by the DuPont Company. This armoring helps to assure that communicationbetween controller 66 and reservoirs 18 remains in effect during animpact event. Post-impact communications are further aided by redundancyin the control system. Specifically, four independent sets of primaryconductors, 79 a-d, extend from controller 66 to reservoirs 18 protectedby sheath 82. Moreover, an H-conductor, shown at 81 in FIG. 5, extendsbetween reservoirs 18. Thus, if one or both of the primary conductors 79a-b, or 79 c-d, extending to one of reservoirs 18 should become severed,H-conductor 81 will be available to carry the initiation signal from theundamaged lines to both of reservoirs 18.

As noted above, an important feature of the present invention resides inthe fact that the control parameters include not only vehicle impact, asmeasured by an accelerometer such as that shown at 70 in FIG. 9, butalso vehicle speed, as measured by means of speed sensors 74, also shownin FIG. 9. Speed sensors 74 may advantageously be existing sensors usedwith an anti-lock braking system or vehicle stability system.Alternatively, speed sensors 74 could comprise a global positioningsensor or a radar or optically based ground-sensing system.Accelerometer 70, as noted above, could be used with a conventionaloccupant restraint airbag system, thereby maximizing use of existingsystems within the vehicle. Advantageously, accelerometer 70 may be anamalgam of two or more accelerometers having differing sensing ranges.Such arrangements are known to those skilled in the art and suggested bythis disclosure. At least a portion of the various sensors could eitherbe integrated in controller 66 or distributed about vehicle 10.

FIG. 6 shows a sequence which is used according to one aspect of thepresent invention for activating a release of fire suppressant agent.

Beginning at block 100, controller 66 performs various diagnostics onthe present system, which are similar to the diagnostics currentlyemployed with supplemental restraint systems. For example, varioussensor values and system resistances will be evaluated on a continuousbasis. Controller 66 periodically moves to block 102, wherein thecontrol algorithm will be shifted from a standby mode to an awake modein the event that a vehicle acceleration, or, in other words, an impact,having a magnitude in excess of a relatively low threshold is sensed byaccelerometer 70. Also, at block 102 a backup timer will be started. Ifthe algorithm is awakened at block 102, controller 66 disables manuallyactivatable switch 54 at block 104 for a predetermined amount of time,say 150 milliseconds. This serves to prevent switch 54 frominadvertently causing an out-of-sequence release of fire suppressionagent. Note that at block 104, a decision has not yet been made todeploy fire suppression agent 22 as a result of a significant impact.

At block 106, controller 66 uses output from accelerometer 70 todetermine whether there has been an impact upon vehicle 10 having aseverity in excess of a predetermined threshold impact value. Such animpact may be termed a significant, or “trigger”, impact. If an impactis less severe than a trigger impact, the answer at block 106 is “no”,and controller 66 will move to block 105, wherein an inquiry is maderegarding the continuing nature of the impact event. If the event hasended, the routine moves to block 100 and continues with thediagnostics. If the event is proceeding, the answer at block 105 is“yes”, and the routine loops to block 106.

If a significant impact is sensed by the sensor system includingaccelerometer 70 and controller 66, the answer at block 106 will be“yes.” If such is the case, controller 66 moves to block 108 wherein thestatus of a backup timer is checked. This timer was started at block102.

Once the timer within controller 66 has counted up to a predetermined,calibratable time on the order of, for example, 5-6 seconds, controller66 will cause propellant 92 to initiate delivery of fire suppressantagent 22, provided the agent was not released earlier. Propellant 92 isactivated by firing an electrical squib so as to initiate combustion ofa pyrotechnic charge. Alternatively, a squib may be used to pierce, orotherwise breach, a pressure vessel. Those skilled in the art willappreciate in view of this disclosure that several additional means areavailable for generating the gas required to expel fire suppressantagent 22 from tank 90. Such detail is beyond the scope of thisinvention. An important redundancy is supplied by having two squibslocated within each of tanks 90. All four squibs are energizedsimultaneously.

The velocity of the vehicle 10 is measured at block 110 using speedsensors 74, and compared with a low velocity threshold. In essence,controller 66 processes the signals from the various wheel speed sensors74 by entering the greatest absolute value of the several wheel speedsinto a register. This register contains both a weighted count of thenumber of samples below a threshold and a count of the number of samplesabove the threshold. When the register value crosses a threshold value,the answer at block 110 becomes “yes.” In general, the present inventorshave determined that it is desirable to deploy fire suppression agent 22prior to the vehicle coming to a stop. For example, fire suppressionagent 22 could be dispersed when the vehicle slows below about 15 kph.

At block 112, controller 66 enters a measured vehicle acceleration valueinto a second register. Thereafter, once the acceleration register valuedecays below a predetermined low g threshold, the answer becomes “yes”at block 112, and the routine moves to block 114 and releases firesuppressant agent 22. In essence, a sensor fusion method combines allavailable sensor information to verify that the vehicle is approaching ahalt. The routine ends at block 116. Because the present firesuppression system uses all of the available fire suppression agent 22in a single deployment, the system cannot be redeployed withoutreplacing at least reservoirs 18.

FIG. 6 does not include the activation of occupant restraints 48 and 50,it being understood that known control sequences, having much differenttiming constraints, may be employed for this purpose. In point ofcontrast, the low velocity threshold allows the present system todeliver the fire suppression agent while the vehicle is still moving,albeit at a very low velocity. This prevents the rear wheels of thevehicle from shadowing, or blocking dispersion of fire suppressant agent22. Also, in many cases, a vehicular fire may not becomewell-established until the vehicle comes to a halt.

As shown in FIG. 10, vehicle 200 has controller 204 for operating anonboard fire suppression system. As shown in FIG. 11, a supply of firesuppression agent 206 is contained within reservoirs 208, with only onereservoir 208 being shown. Propellant 210 provides energy for forcingagent 206 from reservoir 208 under pressure when so directed bycontroller 204.

Reservoir 208 has a combination fill plug and control valve inserted inan upper wall, 212. As shown in FIG. 12, upper wall 212 has a threadedinsert, 216, mounted therein. In a preferred embodiment, reservoir 208is formed as fiber-reinforced resin composite, for the purpose of savingweight and avoiding corrosion in a difficult automotive environment.

As shown in FIGS. 12 and 13, control valve 218 is mounted within a valveholder 220, which is itself threaded into threaded insert 216. Valveholder 220 has a discharge port, 232, which allows gases to enter andleave reservoir 208 as described herein.

Control valve 218 includes three valve elements, with all three valveelements being mounted within valve body 240 which is mounted withinvalve holder 220. The first valve element is an inward-opening poppet,244, which seats on median bulkhead 248 of outward-opening poppet 254.Inward-opening poppet 244 cooperates with vacuum orifice 250 (FIG. 13)formed in median bulkhead 248 of outward-opening poppet 254, toestablish a minimum pressure value for the gas within reservoir 208. Inaid of this objective, compression spring 246 urges inward-openingpoppet 244 into contact with median bulkhead 248, so as to prevent gasesfrom leaving reservoir 208. This is important when propellant 210functions, because otherwise suppressant agent would be lost throughcontrol valve 218. In essence, inward-opening poppet 244 functions as avacuum responsive element to maintain minimum pressure within reservoir208 during standby operation of the present onboard fire suppressionsystem. In so doing, inward-opening poppet 244 prevents undue working,or perhaps even work hardening, of reservoir 208 due as a result offlexure incurred at low pressure resulting from altitude ormeteorological changes.

Outward-opening poppet 254 functions as both a standby pressure reliefelement having an outwardly-opening poppet, and an outward-closingpoppet responsive to high rate flow of suppressant agent 206. Outwardopening poppet 254 is positioned against valve body 240 at sealingsurface 254 a, by means of compression spring 258. When pressure withinreservoir 208 rises at a slow rate during standby operation, spring 258will be compressed and gas or other fluid will be allowed to flowthrough control passage 242, past sealing surface 254 a, and thenthrough discharge port 232. If, however, propellant 210 activates, thehigh flow of suppressant agent 206 leaving reservoir 208, which isaccompanied by a high dynamic pressure, will cause poppet 254 to moveupwardly so as to engage sealing surface 254 b with upper surface 240 aof valve body 240, thereby preventing an outflow of suppressant agent206 through discharge port 232. Poppet 254 is thus seen to be adual-mode poppet functioning as a type of spool valve.

FIG. 14 shows an externally located propellant, 300, which preferablycomprises a cold gas inflator. Controller 204 operates valve 304 toallow compressed gas within propellant 300 to travel through conduit 308into reservoir 208. In this embodiment, multi-function control valve 218is mounted in a portion of conduit 308.

Although the present invention has been described in connection withparticular embodiments thereof, it is to be understood that variousmodifications, alterations, and adaptations may be made by those skilledin the art without departing from the spirit and scope of the inventionset forth in the following claims.

1. An onboard fire suppression system, comprising: at least onereservoir containing a fire suppressant agent; a propellant, operativelyassociated with said reservoir, for expelling the fire suppressant agentfrom the reservoir under pressure; a distribution system for receivingfire suppressant agent expelled from said reservoir and for distributingthe depressant agent; and a multifunction control valve, operativelyconnected with said reservoir, for maintaining pressure within saidreservoir within a predetermined range during standby operation, withsaid control valve closing in the event that said propellant isactivated.
 2. An onboard fire suppression system according to claim 1,wherein said multifunction control valve comprises a vacuum responsiveelement, a standby pressure relief element, and a high flow closureelement.
 3. An onboard fire suppression system according to claim 2,wherein said control valve extends through a wall of said reservoir,with said control valve comprising: a vacuum responsive element havingan inward-opening poppet; a standby pressure relief element having anoutward-opening poppet; and an outward-closing poppet responsive to highrate flow of the suppressant agent.
 4. An onboard fire suppressionsystem according to claim 3, wherein said outward closing poppet closesin response to an elevated suppressant flow rate and elevatedsuppressant pressure accompanying discharge of said suppressant fromsaid reservoir.
 5. An onboard fire suppression system according to claim3, wherein said inward-opening poppet opens in the event that pressurewithin said reservoir falls below a predetermined minimum pressure, withsaid outward-opening poppet moving to an open position in the event thatpressure within the reservoir exceeds a predetermined maximum staticpressure, and with said high flow-responsive poppet closing in the eventthat pressure produced by said propellant exceeds a predeterminedmaximum dynamic pressure.
 6. An onboard fire suppression systemaccording to claim 3, wherein said inward-opening poppet and saidoutward-opening poppet are resiliently biased into normally-closedpositions, with said outward-closing poppet being resiliently biasedinto a normally-open position.
 7. An onboard fire suppression systemaccording to claim 1, wherein said propellant is housed within saidreservoir.
 8. An onboard fire suppression system according to claim 1,wherein said propellant is external to said reservoir, and saidmulti-function control valve is located within a conduit extendingbetween said reservoir and said propellant.
 9. An onboard firesuppression system according to claim 1, wherein said multifunctioncontrol valve is contained within a filler port plug for said reservoir.10. An onboard fire suppression system according to claim 1, whereinsaid reservoir comprises a fiber-reinforced resin composite.
 11. Anonboard fire suppression system, comprising: at least one reservoircontaining a fire suppressant agent; a propellant, operativelyassociated with said reservoir, for expelling the fire suppressant agentfrom the reservoir under pressure; a distribution system for receivingfire suppressant agent expelled from said reservoir and for distributingthe depressant agent; and a multifunction control valve, operativelyconnected with said reservoir, for maintaining pressure within saidreservoir within a predetermined range during standby operation of saidfire suppression system, with said control valve comprising: a vacuumresponsive element having an inward-opening poppet; and a dual-modepoppet having an outward-opening valve element for standby pressurerelief, and an outward-closing valve element for shutting off flowthrough the multifunction control valve if the propellant is activated.12. An onboard fire suppression system according to claim 11, whereinsaid outward-opening valve element and said outward-closing valveelement comprise opposite ends of a unitary valve spool.
 13. An onboardfire suppression system according to claim 12, wherein saidinward-opening poppet cooperates with a vacuum orifice formed in saidvalve spool to establish a minimum pressure value for said reservoir.14. An onboard fire suppression system according to claim 11, whereinsaid reservoir comprises a fiber-reinforced resin composite.